The present invention relates generally to hydraulic control systems for refuse compacting apparatuses, and more particularly to a simplified hydraulic control system and valve useful in such compacting apparatuses.
The use of hydraulically-powered devices for compacting refuse is well known. One such system is illustrated in FIG. 1. FIG. 1 shows a refuse compacting apparatus mounted on a truck and including a compaction chamber 10 and a refuse accumulating zone 12 communicating with the compaction chamber. A link panel 14 is mounted with the compaction chamber and is adapted to rotate therein about pivot point 16. A packer panel 18 is connected to the link panel and is adapted to rotate with respect to the link panel about pivot point 20. A hydraulic control system controls the movement of the link and packer panels to cause these panels to compact refuse in the compaction chamber and to move the refuse into the refuse accumulating zone. The hydraulic control system includes a supply of high pressure fluid on line 22, a fluid reservoir 24, and two cylindrical motors 26 and 28, each having pistons 30 and 32, respectively, arranged to reciprocate therein in response to fluid pressures on opposite sides of the piston. The first motor 26 has its rod end connected to the packer panel 18 and the second motor 28 has its rod end connected to the link panel 14. A directional control valve 34 has a first operating position 36 for placing the fluid supply in fluid communication with the head end of motor 26 with the rod end of motor 26 and the head end of motor 28 being placed in fluid communication with reservoir 24. The rod end of motor 28 is connected to the supply through a sequence valve 38. The directional control valve 34 has a second operating position 40 for placing the rod and motor 26 and the head end of motor 28 in fluid communication with supply 22, with the head end of motor 26 being placed in fluid communication with reservoir 24. The head and rod ends of motor 28 are connected to a regenerative valve 42.
When the directional control valve 34 is in position 36, fluid will be delivered from supply line 22 to the head end of packer motor 26 with fluid in the rod end of packer motor 26 being delivered to tank 24. The packer motor will continue to operate, rotating packer panel 18 with respect to link panel 14 until the motor reaches its limit of travel. At this point pressure will build up in the head end of motor 26 until a predetermined threshold pressure is reached, causing sequence valve 38 to trip connecting supply 22 to the rod end of link motor 28. Since the head end of motor 28 is connected to reservoir 24, the motor 28 rotates the link panel 14 upward in the compaction chamber, causing the packer panel 18 to push the refuse into the accumulating zone 12. The directional control valve 34 is then shifted by the operator into position 40, causing fluid to be supplied to the rod side of packer motor 26 with the head side of motor 26 being connected to reservoir 24. Simultaneously the head side of link motor 28 is connected to the fluid supply but the rod side of motor 28 is temporarily blocked from evacuating fluid by sequence valve 38 and regenerative valve 42. The packer motor 26 continues to retract until it has reached its limit of travel, causing the packer panel 18 to rotate back into the compaction chamber. Pressure will then build up in the head end of motor 28 until a predetermined threshold level is reached, typically the same as the threshold level for sequence valve 38, causing regenerative valve 42 to trip, placing the rod end of motor 28 in fluid communication with its head end, thus completing a regenerative circuit which will permit the motor 28 to rotate the link panel downward in compaction chamber 10 until it returns to its rest position.
Such prior circuits have worked satisfactorily, but have contained a large number of hydraulic components, and have thus been costly to build and operate.